Rutsuko Yamaguchi

Morphometric analysis of sex differences in contemporary Japanese pelves using multidetector computed tomography

Sex estimation of decomposed or skeletal remains is clearly important in forensic contexts. Recently, contemporary population-specific data has been obtained using multidetector computed tomography (MDCT) scanning. The main purpose of this study was to investigate skeletal pelvic dimorphism in a contemporary Japanese forensic sample and to quantify the accuracy of sex estimation using various pelvic measurements obtained from three-dimensional (3D) CT images. This study used a total of 208 cadavers (104 males, 104 females) of which postmortem CT scanning and subsequent forensic autopsy were conducted between December 2011 and August 2014. Eleven measurements of each pelvis were obtained from 3D CT reconstructed images that extracted only bone data. The measurements were analyzed using descriptive statistics and discriminant function analyses. All except one measurement were dimorphic in terms of sex differences. Univariate discriminant function analyses using these measurements provided sex classification accuracy rates of 62.0-98.1%. The subpubic angle was found to contribute most significantly to accurate sex estimation. Multivariate discriminant functions yielded sex prediction accuracy rates of 63.9-98.1%. In conclusion, the pelvic measurements obtained from 3D CT images of a contemporary Japanese population successfully demonstrated sexual dimorphism and may be useful for the estimation of skeletal sex in the field of forensic anthropology.

Stature estimation from skull measurements using multidetector computed tomographic images: A Japanese forensic sample

The aim of this study was to assess the correlation between stature and cranial measurements in a contemporary Japanese population, using three-dimensional (3D) computed tomographic (CT) images. A total of 228 cadavers (123 males, 105 females) underwent postmortem CT scanning and subsequent forensic autopsy between May 2011 and April 2015. Five cranial measurements were taken from 3D CT reconstructed images that extracted only cranial data. The correlations between stature and each of the cranial measurements were assessed with Pearson product-moment correlation coefficients. Simple and multiple regression analyses showed significant correlations between stature and cranial measurements. In conclusion, cranial measurements obtained from 3D CT images may be useful for forensic estimation of the stature of Japanese individuals, particularly in cases where better predictors, such as long bones, are not available.

Pulmonary Macrophages Attenuate Hypoxic Pulmonary Vasoconstriction via β3AR/iNOS Pathway in Rats Exposed to Chronic Intermittent Hypoxia.

Chronic intermittent hypoxia (IH) induces activation of the sympathoadrenal system, which plays a pivotal role in attenuating hypoxic pulmonary vasoconstriction (HPV) via central β1-adrenergic receptors (AR) (brain) and peripheral β2AR (pulmonary arteries). Prolonged hypercatecholemia has been shown to upregulate β3AR. However, the relationship between IH and β3AR in the modification of HPV is unknown. It has been observed that chronic stimulation of β3AR upregulates inducible nitric oxide synthase (iNOS) in cardiomyocytes and that IH exposure causes expression of iNOS in RAW264.7 macrophages. iNOS has been shown to have the ability to dilate pulmonary vessels. Hence, we hypothesized that chronic IH activates β3AR/iNOS signaling in pulmonary macrophages, leading to the promotion of NO secretion and attenuated HPV. Sprague-Dawley rats were exposed to IH (3-min periods of 4–21% O2) for 8 h/d for 6 weeks. The urinary catecholamine concentrations of IH rats were high compared with those of controls, indicating activation of the sympathoadrenal system following chronic IH. Interestingly, chronic IH induced the migration of circulating monocytes into the lungs and the predominant increase in the number of pro-inflammatory pulmonary macrophages. In these macrophages, both β3AR and iNOS were upregulated and stimulation of the β3AR/iNOS pathway in vitro caused them to promote NO secretion. Furthermore, in vivo synchrotron radiation microangiography showed that HPV was significantly attenuated in IH rats and the attenuated HPV was fully restored by blockade of β3AR/iNOS pathway or depletion of pulmonary macrophages. These results suggest that circulating monocyte-derived pulmonary macrophages attenuate HPV via activation of β3AR/iNOS signaling in chronic IH.

Sex estimation based on scapula analysis in a Japanese population using multidetector computed tomography

Accurate sex estimation based on measurements of dimorphic dimensions in human unknown remains is important as the first step toward making individual identification. The purpose of this study was to assess the sexual dimorphism of the scapula and to quantify the accuracy of sex estimation in a contemporary Japanese forensic sample using scapular measurements based on three-dimensional (3D) computed tomographic (CT) images. A total of 218 cadavers (109 males, 109 females) that underwent postmortem CT and subsequent forensic autopsy were used. Ten scapular measurements were performed on 3D CT reconstructed images that extracted only bone data, and were analyzed using descriptive statistics and discriminant function analyses (DFA). All measurements were dimorphic in terms of sex differences. Univariate DFA provided sex classification accuracy rates of 75.7-91.3%. Stepwise DFA yielded sex prediction accuracy rates of 93.1-94.5%. In conclusion, the scapular measurements using 3D CT images of a contemporary Japanese population may be useful for the estimation of skeletal sex in the field of forensic anthropology.

Sexual determination based on multidetector computed tomographic measurements of the second cervical vertebra in a contemporary Japanese population

Accurate sex estimation is important in forensic investigation to determine the identity of unknown individuals. The aim of this study was to investigate the accuracy of sex assessment based on measurements of the second cervical vertebra (C2) using computed tomographic (CT) images in a Japanese population and to develop discriminant function formulae. The data were collected from 224 Japanese cadavers (112 male subjects, 112 female subjects) on which postmortem CT scanning and subsequent forensic autopsy were performed. Nine CT measurements of the C2 were performed for CT images of each subject. The measurements were assessed using descriptive statistics and discriminant function analyses (DFA). All of the measurements demonstrated significant sexual dimorphism. Multiple DFA with stepwise variable selection resulted in multivariable models; a five-variable model reached an accuracy rate of 92.9%. Our results suggest that metric analysis based on CT images of the C2 can accurately determine the sex from the human skeletal remains in a contemporary Japanese population and may be useful for sex estimation in forensic anthropology.

Stature estimation in a contemporary Japanese population based on clavicular measurements using multidetector computed tomography

The aims of this study was to assess the correlation between stature and clavicular measurements in a contemporary Japanese population using three-dimensional (3D) computed tomographic (CT) images, and to establish regression equations for predicting stature. A total of 249 cadavers (131 males, 118 females) underwent postmortem CT scanning and subsequent forensic autopsy between October 2011 and May 2016 in our department. Four clavicular variables (linear distances between the superior margins of the left and right sternal facets to the anterior points of the left and right acromial ends and between the superior margins of the left and right sternal facets to the left and right conoid tubercles) were measured using 3D CT reconstructed images that extracted only bone data. The correlations between stature and each of the clavicular measurements were assessed with Pearson product-moment correlation coefficients. These clavicular measurements correlated significantly with stature in both sexes. The lowest standard error of estimation value in all, male, and female subjects was 3.62cm (r2=0.836), 3.55cm (r2=0.566), and 3.43cm (r2=0.663), respectively. In conclusion, clavicular measurements obtained from 3D CT images may be useful for stature estimation of Japanese individuals, particularly in cases where better predictors, such as long bones, are not available.

Differences in biomechanical properties and thickness among frontal and parietal bones in a Japanese sample

The aim of this study was to assess the mechanical properties and thickness of adult frontal and parietal bones. The heads of 114 Japanese cadavers (78 male cadavers and 36 female cadavers) of known age and sex were used. A total of 912 cranial samples, 8 from each skull, were collected. Samples were imaged using multidetector computed tomography to measure sample thickness. The fracture load of each sample was measured using a bending test with calculation of flexural strength. Statistical analyses demonstrated no significant bilateral difference in either the mechanical properties or thickness of frontal or parietal bones. The mechanical properties and thicknesses of frontal bones were significantly greater than those of parietal bones regardless of sex. Therefore, the skull may have a great ability to resist frontal impacts compared with parietal impacts. In female samples, parietal bones were found to have a more uniform structure when compared with male samples. Male parietal bones were found to be thicker at medial sites than at lateral sites. This study also revealed parietal bones at lateral sites in female samples were thicker than in male samples. No strong association was observed between age and flexural strength of frontal or parietal bones. However, the fracture load was negatively correlated with age most likely due to the reduction of thickness.

Fluid-Fluid Level and Pericardial Hyperdense Ring Appearance Findings on Unenhanced Postmortem CT Can Differentiate Between Postmortem and Antemortem Pericardial Hemorrhage.

OBJECTIVE The objective of this study was to determine whether selected postmortem unenhanced CT findings can discriminate between antemortem and postmortem pericardial hemorrhage. MATERIALS AND METHODS Thirty-one consecutive cases of postmortem CT followed by autopsy identifying at least 50 mL of hemorrhaged blood were reviewed. Seven cases were classified as postmortem pericardial hemorrhage secondary to chest compression (postmortem group), and 24 cases were classified as antemortem pericardial hemorrhage secondary to disease or trauma (antemortem group), on the basis of autopsy findings. Postmortem CT findings of pericardial hemorrhage were classified as stratification comprising upper low-density and lower high-density areas (i.e., fluid-fluid level) and a high-density concentric ring (i.e., pericardial hyperdense ring). Diagnostic values for detecting antemortem or postmortem pericardial hemorrhage using this classification system, along with attenuation (in Hounsfield units) of pericardial hemorrhage lesions and the presence or absence of flattened heart sign on postmortem CT, were measured. RESULTS There were statistically significant differences in fluid-fluid level and pericardial hyperdense ring between the postmortem and antemortem groups (p < 0.001). The sensitivity, specificity, positive predictive value, and negative predictive value of fluid-fluid level for detecting postmortem pericardial hemorrhage were 86%, 96%, 86%, and 100%, respectively. The mean attenuation of pericardial hemorrhage lesions differed statistically significantly between the groups (p = 0.004). The presentation of the flattened heart sign did not differ statistically significantly between the groups (p = 0.681). CONCLUSION Fluid-fluid level and pericardial hyperdense ring on postmortem CT, combined with attenuation, are useful for differentiating between antemortem and postmortem pericardial hemorrhage secondary to chest compression.

An Unusual Autopsy Case of Cytokine Storm–derived Influenza–associated Encephalopathy Without Typical Histopathological Findings: Autopsy Case Report

Cytokine storm-derived influenza-associated encephalopathy is a severe complication, affecting not only the brain but also multiple systemic organs including the heart and lungs. Hundreds of Japanese children are afflicted by influenza-associated encephalopathy every year. Influenza-associated encephalopathy can be diagnosed by pathological changes, such as advanced brain edema and disruption of astrocytic projections, which is known as clasmatodendrosis. In the present case, despite the absence of significant histopathological findings in the brain, the diagnosis of influenza-associated encephalopathy was made on the basis of autopsy findings such as brain swelling, pathological findings including diffuse alveolar damage, and increase in the concentrations of interleukin-6 in both the serum and cerebrospinal fluid. In this case, the interval from high fever to death was approximately 7 hours and may have been too short for histopathological features to develop. This is an unusual autopsy case of cytokine storm-derived influenza-associated encephalopathy without typical histopathological findings.

An unusual autopsy case of lethal hypothermia exacerbated by body lice-induced severe anemia.

Pediculus humanus humanus (known as body lice) are commonly found in the folds of clothes, and can cause skin disorders when they feed on human blood, resulting in an itching sensation. Body lice are known as vectors of infectious diseases, including typhus, recurrent fever, and trench fever. An infestation with blood-sucking body lice induces severe cutaneous pruritus, and this skin disorder is known as “vagabond’s disease.” A body lice infestation is sometimes complicated with iron deficiency anemia. In the present case, a man in his late 70s died of lethal hypothermia in the outdoors during the winter season. The case history and autopsy findings revealed that the cause of the lethal hypothermia was iron deficiency anemia, which was associated with a prolonged infestation of blood-sucking body lice. Also, he had vagabond’s disease because the skin on his body was abnormal and highly pigmented. This is an unusual autopsy case since the body lice contributed to the cause of the death.